(a) Field of the Invention
The present invention relates to a bumper back-beam for a vehicle.
(b) Description of the Related Art
In general, a vehicle bumper back-beam is a shock-absorbing part disposed on the front or the rear of the vehicle to minimize physical damage to a vehicle by elastically deforming during a vehicle collision at a low speed, protect passengers and minimize deformation of a vehicle by absorbing shock in a collision with another vehicle or a fixed object. When the strength of the bumper back-beam is increased, the weight and the cost are increased, conversely, when the weight and the cost are decreased, the strength is decreased, therefore, the function cannot be sufficiently achieved. Accordingly, a Glass fiber Mat Thermoplastic (hereinafter “GMT”) that is a lighter material and strong has been developed.
The GMT is an advanced material that is a plate-shaped composite composed of polypropylene resin, which is common resin, and a glass fiber mat reinforced material. In particular, molten polypropylene extruded by a T-die and a glass fiber non-woven mat are directly impregnated, providing an improved bonding force with the resin. Further, the strength of the glass itself is reinforced in a mat type, and the strength is greater than other materials. Generally, GMT has a light weight and the degrees of freedom in design are features of plastics, and the thermoplastic resin and also provide a high productivity and reusability.
A front bumper back-beam protects against a high-speed collision, however, when it is made of GMT having improved shock resistance, the bumper back-beam breaks in a high-speed collision, and therefore it cannot be used by itself. Recently, a back-beam manufactured by inserting steel in GMT has been developed however; there is a limit in reducing weight. Furthermore, forming different materials simultaneously increases the difficulty of the process.
The above information disclosed in this section is merely for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.